Re: .30-06 Maximum Average Pressure

16 August 2004, 21:08

I just want to point out that M98's numbers are stated as being in PSI, and everyone elses are stated as being in CUP.
These are two VERY different ways of measuring pressure, and do not have a general way of converting one to the other. This is a plea for beginners to realize that they can NOT up the powder load by 20% to match these numbers.

Now with the availability of the strain gauge pressure systems (Oehlers M43 and RSI PressureTrace), reloaders are finding out just how much over-pressure some of the old load data really is, and that smokeless powder is VERY inconsistant in reproducing peak pressures, while still giving fairly consistant muzzle velocities. There have been several articles written recently about this in the magazines; please realize that the results shouldn't be ignored.

15 August 2004, 06:36

bartsche

A lot of it has to do with the hardness of the brass

If memory serves me correctly There were advancements in cartridge brass hardness in the late 40s early 50s.The word went out amoung reloaders that the .308 was designed around "high intencity brass" and the 06 was not and that we should take care when using .308 cases made from 06 brass. OK, Who wants a chopped down 06 anyway. That was the thought of that day for a lot of gun nuts.
The brass plus the mod. 95 and soft 03s tells the story. I use to hunt with a Mod. 95 in 30-06 and case stretch was a standard happening. I always down loaded it.

roger

15 August 2004, 03:37

DUK

I remember reading somewhere that they respect the maximum pressure but achieve somehow (rattlin' and shakin'?) to get more of a slower powder into the case, like an overcompressed load.

Anyway, like already stated, the 30/06 is such a perfect and wellperforming cartridge (they knew what they did in those days, even without CNC and fancy simulations) that there is just no need to play risky games, IMHO. Again, it's all about bullet placement.

15 August 2004, 00:53

<eldeguello>

Quote:

I realize that the limit on the .30-06 was probably put in place because of the number of older service rifles around that might not be able to handle the pressure, but it still seems like they could sell higher pressure ammo to work in todays guns similar to the .38 Special and .38 Special +P loads.

They do! It's called "Light Magnum" or "Hi-Energy" ammo. Made by Hornady and Federal respectively. If you don't think this stuff is loaded hotter, just fire some of it!

14 August 2004, 18:29

Wstrnhuntr

Quote:

I realize that the limit on the .30-06 was probably put in place because of the number of older service rifles around that might not be able to handle the pressure, but it still seems like they could sell higher pressure ammo to work in todays guns similar to the .38 Special and .38 Special +P loads.

If that were the case then I doubt that they would rate the 280 @ 50,000 cup as well, which they do.

In the end all that really matters, if you reload that is, is that you are keen to reading pressure signs and ultimatley "your" rifle will tell you where the max is.

Its funny really how much creedence people give "the books" today. I just watched a show on the history channel that gave details of the earliest snipers, one of which picked off a british General from 300 yds with a musket during the revoloutionary war. A MUSKET! a ,30 cal slug @ 2500-2800 fs is so underrated today.

14 August 2004, 17:27

Pecos41

Goe - You history lesson on the /06 is good and right on, but I have to disagree about now shooting the LOW NUMBER 03's. There are a lot of them around shooting today. What actually should be done with this series of rifles is be very careful about the pressure levels of the ammo put thru them.

These are NOT rifle actions to get cute with. They would make great cast bullet rifles etc.

Respect the aged is the byword here.

14 August 2004, 17:18

Geo.

The .30-'03 cartridge was developed for use in the M1903 rifle. The rifle had a 24" barrel and the cartridge operated at fairly modest pressure, about 47,000 c.u.p. The original cartridge had a long neck that held a long 220 grain round-nosed bullet. The bullet was a carryover from the Krag.

When the .30-'06 cartridge was adopted (1906), the neck was shortened, the bullet weight reduced to 150 grains, the bullet changed to a spitzer, and the pressure was upped to 50,000 c.u.p. The existing rifles were called back in and the barrel turned in one opr two threads( I have forgotten which) and rechambered to the shorter chamber. That left the barrels 23.75".

Winchester originally chambered the M95 in .30-'03 and then changed to the .30-'06, after, of course, the military did their number. The M95s thus chambered developed a reputation for getting excessive headspace quickly because of the relatively weak design steels for a high pressure cartridge. The M95 worked fine in .40-40 Krag and some other cartridges, though.

Somewhere along the line, Winchester introduced the M54 bolt-actioned sporter in .270 Win. In the .270 Win, they retained the longer neck of the '03 cartridge even though the '06 had been in service a long time. At the outset, the .270 Winchester was a factory hot-shot and ran about 52,000 c.u.p. This was an advertising/promotional gimmick for the day. Today, it would not raise any eyebrows.

The only older service rifles that could not handle the pressures were that way because of the heat-treating, not because of the cartridge. If you have one of these M1903s called "low numbered," you should not shoot it. Put it on the wall and enjoy looking at it.

It stood then, and it stands still today, that pressure limits are determined by the weakest link in the system--the brass cartridge case. Even though breeching methods have improved, leaving much less cartridge unexposed, if the brass case gives way, so does the rifle.

Hope that helps.